Drane Nikac (l.), 67, was killed in a DWI accident.

The NYPD detective charged with drunkenly mowing down a Bronx woman is an alcoholic once ordered into rehab after a boozed-up argument, the Daily News has learned.

Detective Kevin (Spike) Spellman, police and other sources said, got into a row inside a bodega about three years ago.

Supervisors called to the scene determined he had been drinking and he was slapped with departmental charges, docked 30 days' pay and sent to rehab, sources said.

Last Friday, he was arrested after striking and killing Drane Nikac, a 62-year-old grandmother, at a Kingsbridge intersection.

Spellman, off-duty at the time, was charged with DWI and vehicular manslaughter. His blood alcohol level was 0.21, more than 2-1/2 times the legal limit.

Spellman, 42, was so drunk he thought Nikac was a man and said, "he came out of nowhere," authorities said.

Spellman has been in hiding since the accident. His union lawyer's office said Tuesday it is no longer representing him.

The 22-year veteran has a reputation as a topnotch investigator with a joint task force that tracks down fugitives. He has battled problems with alcohol for several years, sources said.

In an accident 13 years ago, he and a friend were heading home after an early-morning workout in Yonkers when he rammed his Nissan into another car, court records show.

A teen in the second car needed reconstructive surgery to repair wounds from the glass shards that struck her face, records show. The records don't say if alcohol was involved in that accident.

Spellman said he didn't see that car, driven by the teen's father, "until it was directly in front of him." Spellman's insurance company ultimately paid for the family's medical bills.With John Marzulli